Bifilar pancake coil overunity experiment

[gyulasun]

...
Remember that the input signal drops at resonance from 20v pp to 600 mv (and the current increases proportionally) and nevertheless I observe the same voltage from the open test probe feeling electric fields or with the "looped probe" feeling magnetic fields. From this I conclude that each field, the electric field and magnetic field that the probe detect, don't depend neither on the input voltage alone nor on the input current alone but depend on both. How is another question. 

Hi F6FLT,

Yes, the EM field strength also surely depends on the power fed into the coil or coax loop at  or near resonance. With a 50 Ohm generator output impedance only a few Ohm (or even under 1 Ohm) resonant impedance is connected in parallel, so a hugh voltage divison takes place via the internal impedance of the generator towards the coil, hence the small 600 mVpp amplitude remaining across the generator output i.e. across the coil input or across the coax loop input.
And a 600 mVpp voltage can maintain only a certain amount of current, certainly much less than the 20 Vpp would.

If you had a generator with much less than say 1 Ohm output impedance, then there would be much less internal voltage drop across the internal impedance at resonance, so much more voltage would be available across the coil hence the power feeding the coil would be much higher.  I am sure you know these, sorry. But then the EM field would surely be stronger than now from the 50 Ohm generator.

It's funny to see the strong resonance without the least effect on the amplitude but with a strong effect on the phase.
At resonance the signal probe is 90° out of phase with the input signal from the generator. When we change the frequency by only 2.5%, the signal probe becomes in phase or in opposition with the input signal (depending on the frequency lower or higher than the resonant frequency). 

Yes the phase changes drastically around the resonance, it should because either inductive or capacitive reactance starts dominating the moment you detune the generator from the resonant requency. The voltage amplitude can remain quasi unchanged near the resonance because the figure of merit, Q is relatively low due to the 50 Ohm generator impedance.  This 50 Ohm simply 'defines' the impedance the coil 'sees' at and in the vicinity of the resonance. See my further comment at the bottom too.

"If you feed a DC current into the bifilar coil, where do you think the static poles would appear?"

I don't understand the question in the context, no current is possible here in DC. 

I simply meant a case when there is only a static DC current fed into your bifilar coil, then where the magnetic poles develop?  I asked this to reveal the closeness of the magnetic poles to each other so they can combine easily.   But let's put this question for a later time if you wish.

I had read your reply on the measurements but didn't yet take time to study enough the method. 

Okay, thanks.

I remain troubled by the question of the probed magnetic field that doesn't increase at resonance while the current is increasing. The current goes the same direction in both wires and the magnetic field is proportional to the current only. So we should have an increase. May be it's a question of phase difference between the wires...

I think it is also a question of the phase difference between coil input current and input voltage, when they are in phase the real power should be at a maximum but there is the generator impedance which prevents high current both at resonance or at off resonance (as long as at off resonance the capacitive or inductive reactance will not be higher than 50 Ohm, beyond that range already the reactances would infuence hence define coil current).

Gyula

[ayeaye]

There is no need for input and output part, and only one script is necessary.

Because when the power is positive, it's input, and when the power is negative, it's output. So the script becomes the following.

#Time between samples in ns
XU = 0.4
#Voltages are in mV
YU1 = YU2 = 1000.0
#Resistor resistance in ohms
R = 47.0
#Frequency in Hz
F = 1000.0

ei = eo = 0.0
f1 = open("input1.txt")
f2 = open("input2.txt")
while (True):
  s1 = f1.readline()
  s2 = f2.readline()
  if (len(s1) < 2 or len(s2) < 2): break
  vs = float(s1) * YU1
  vr = float(s2) * YU2
  vl = vs - vr
  pl = vl * vr / R / 1000
  if (pl >= 0): ei += pl
  if (pl < 0): eo += pl
f1.close()
f2.close()
ei *= XU / 1000000
print("Input power was %.4f uW" % (F * ei))
eo *= -1 * XU / 1000000
print("Output power was %.4f uW" % (F * eo))

The following is the trinket with that script. This script needs a full cycle of channel 1 in input1.txt and channel 2 in input2.txt, or maybe less if after some time both are 0. You can see that the results are exactly the same as when doing it separately for input part and output part.

https://trinket.io/python/a90a61d84e

This script can be used to calculate input and output power of the coil also when the signal is sine, or when the signal is whatever, it's universal. No need to separate any parts.

Do you see

I took the figure below from wikimadia commons, By 121a0012 - self-made, after w:Image:ACPower03CJC.png by User:C J Cowie, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2866717 .

[ayeaye]

The following is the Inkscape script trinket with the channel 2 data above. Assuming that the output of the oscilloscope is voltages, so that the output of that script can be directly used for the input of the script for digital oscilloscope. That is, it supposed to provide the same sample list as in the csv file taken from the digital oscilloscope. So these who have analog oscilloscopes can do the calculations the same as if they had digital oscilloscope. All i know the people here use, are digital desktop oscilloscopes and old analog oscilloscopes, i have not seen anyone here using anything else.

https://trinket.io/python/a8d33f8989

This is what i offer, two Python scripts to calculate input and output power of a coil.

Seeing phi is a way to estimate the power efficiency when the signal is sine. With other waveforms, with digital oscilloscope, one can measure voltage on the coil and voltage on the resistor, then multiply these channels and show them as the math channel. This enables to quickly visually estimate the power efficiency, comparing the positive and negative areas of the waveform on the math channel.

It were easy to make power calculations if the oscilloscope did calculate positive and negative areas of the math channel. Unfortunately cheaper scopes cannot do calculations on the math channel at all, and cannot even output the math channel as csv. The accuracy of any calculations done by the scope may also be questionable on some scopes. So in that case there is no other way than to get the waveform data of both channels as csv, and do the calculations from that.

The more expensive scopes most likely provide more, and some may be able to accurately calculate positive and negative areas of the math channel. For that it were enough if they were like capable of calculating the area of the math channel waveform in a range. But that written here, should be so that everyone can do that, so that the results can be replicated by other people, and i think most here use rather cheap digital scopes with not many capabilities. Some use even analog scopes, like me, so i provided a method for them as well.

[F6FLT]

The resonance frequency of my bifilar coil when working as a normal monofilar is 2330 KHz. Its capacity is 55 nF thus its inductance is 84.8 nH ( L = 1/(C*ω²)  ).

But with the bifilar coil connected as specified in reply #153, the resonance drops to 28Khz.
I have tried many LTspice simulations to get an equivalent circuit. The only LTspice simulation that fits what I observe needs the inductance (not the capacitance) to be multiplied by 5000.

It's indeed impossible to reach a so low resonance with values as small as 55nf and 84.8nH. The schematic is very simple but problematic. Did I miss something? (Otherwise imho it's useless to play with bifilar coils until we obtain an explanation for this elementary result).

[ayeaye]

It's indeed impossible to reach a so low resonance with values as small as 55nf and 84.8nH. The schematic is very simple but problematic. Did I miss something? (Otherwise imho it's useless to play with bifilar coils until we obtain an explanation for this elementary result).

My guess is that because of the capacitance, some of the induction happens Lenz free, and this enables very high inductance. This conjecture is just intuitive, not really thought through at all. But the matter is that there seems to be by now no better explanation.

Please measure the powers at resonance. Either the voltage on the coil and on the resistor, and phi between them, multiplication of them, or such. Not that there should be overunity, but this is an anomalous phenomenon, so worth to study. It is not excluded that in certain conditions there may be overunity, with a different resistance of the resistor, or whatever else.

Yes we don't know, and it's worth to research something, when we don't know.